Prior methods and apparatus for moving teeth can be less than ideal in at least some respects. Although orthodontic shell appliances can be effective in moving teeth, complex tooth movements may be benefit from the use of attachments on the teeth that engage the appliance to move the tooth. Although attachments can be effective, complex tooth movements may require multiple attachments on the teeth, which can be somewhat cumbersome and unsightly for the patient, as well as difficult for the orthodontic practitioner to apply. Furthermore, prior attachments can be sensitive to manufacturing variations resulting in unpredictable or inconsistent forces applied to teeth. It would be helpful to provide more versatile and reliable attachments, allowing the orthodontic shell appliances to move teeth more precisely and with less need to replace attachments during treatment.